Copolymers of vinyl acetate and ethylenically unsaturated carboxylic compound havingat least one carboxyl group, compositions prepared from said copolymers and sizing of textile yarns with said compositions



United rates Patent 9 COPOLYMERS OF VINYL ACETATE AND ETHYL- ENICALLY UNSATURATED CARBSXYLIC CGM- PGUND HAVING AT LEAST ONE CARBOXYL GROUP, CQIVIPGSlTlONS PREPARED FRGM SAID COPOLYMERS AND SlZlNG F TEXTTLE YARNS WITH SAID CGWGSITIGNS Milton 3. Scott, Lexington, and Alton E. Peacock, Waltham, Mass, assignors to Monsanto Chemical (Zompany, St. Louis, Mo., a corporation of Delaware No Drawing. Application February 8, 1952, Serial No. 270,756

10 Claims. (Cl. Hill-35.7)

The present invention relates to novel polymeric materials and processes of preparing such materials. The present invention also relates to processes of sizing textile yarns with such materials to prepare the yarns for weaving. The present invention flso relates to the yarns so produced.

it has been proposed in U. S. Patent No. 2,263,598 to prepare high molecular weight copolymers of vinyl acetate and crotonic acid by mass polymerization. In this patent it is stated that the copolymers have a higher softening point and more resistance to water than polyvinyl acetate per se. The copolymers described in this patent have properties which make them desirable for certain uses, but it has been found that when alkali metal salts of such copolymers which contain very high percentages of vinyl acetate are prepared, and heated at elevated temperatures, for example, 300' F., for relatively short periods of time, such salts are difficult to dissolve in water in contrast to the initial alkali metal salts of the copolymers. This latter property of the alkali metal salts of the copolymers of U. S. Patent No. 2,263,598, makes them unsuitable for certain uses where ready solubility or dispersibility in water after a heat treatment is essential. In accordance with the present invention there is provided novel polymeric materials which dissolve readily in aqueous solutions of caustic soda or sodium carbonate for ready application, and which may be dried at elevated temperatures without losing their ability to redissolve or redisperse in water. The properties of the polymeric materials of the present invention make the polymeric materials especially suit- :able for sizing textile warp yarns since they are readily applied, have good adhesion and may be dried at elevated temperatures without rendering them resistant to removal from the yarn, after a weaving operation, by :simple scouring with warm water.

It is, accordingly, one object of this invention to provide novel polymeric materials, and particularly novel polymeric materials which are especially useful in the sizing of textile warp yarns and which are readily removed from such yarns, after having been heated at elevated temperatures, by simple scouring with warm water.

It is a further object of this invention to provide improved compositions for sizing textile warp yarns, especially cellulosic warp yarns.

It is a further object of this invention to provide processes for preparing the novel polymeric materials and compositions referred to in the foregoing objects.

It is a further object of this invention to provide an improved process of sizing textile warp yarns, especially cellulosic warp yarns, to prepare them for weaving.

It is a further object of this invention to provide sized textile warp yarns, especially 'sized cellulosic warp yarns, which are covered with a tough, adherent and 2,806,020 Patented Sept. 10, 1957 ice flexible sizing agent which protects the yarns from mechanical damage during weaving and is readily removed from the yarns by a simple scouring in warm water.

Still further objects and advantages ofthis invention will become apparent from the following description and the appended claims.

It has presently been found that by preparing a low molecular weight copolymer of from about to 98 mol percent of vinyl acetate and from about 10 to 2 mol percent of an unsaturated organic carboxylic compound containing from 3 to 9 carbon atoms and having at least one carboxyl group as, for example, a compound such as crotonic acid, the copolymer has especially valuable properties when it is employed in the form of its alkali metal salts in the sizing of textile warp yarns with the exception of linear synthetic polyamide yarns such as nylon yarns. By low molecular weight copolymer is meant a copolymer having a molecular weight such that a molar solution of the copolymer in 2B alcohol (99 /2% ethanol, /2% benzene) has a viscosity below 18 centipoises but not below 7 centipoises at 20 C. If the copolymer has a molecular weight such that a molar solution thereof in 99.5% ethanol and 0.5% benzene has a viscosity appreciably above 18 centipoises at 20 C., the alkali metal salts of such copolymer lose their water solubility on prolonged heating at temperatures of 200 F. and higher and this makes such copolymer and its alkali metal salts unsuitable for certain uses, especially for sizing textile warp yarns as will become more fully apparent in the following description. Hence, the copolymers of this invention and theirvalkali metal salts exhibit unusual properties as compared to higher molecular copolymers which properties could not be predicted from the properties of the high molecular weight products.

The term molar solution of the copolymer as used above and in the following description. and appended claims is intended to mean a formula weight in grams of the monomers in the copolymer in 1 liter of solution. The formula weight in grams is determined by multiplyin the gram molecular weight of each monomer in the copolymer by the mol percent of the monomer in the copolymer and adding the resulting figures. Thus, the formula weight in grams of a copolymer of 98 mol percent vinyl acetate and 2 mol percent crotonic acid is equal to the gram molecular weight of vinyl acetate (86 grams) multiplied by 0.98 (mol percent) plus the gram molecular weight of crotonic acid (86 grams) multiplied by 0.02 (mol percent), or 86 grams.

The mol ratio of vinyl acetate to unsaturated organic carboxylic compound in the copolymer is critical when the copolymer is to be used for sizing textile warp yarns. Thus, if the copolymer contains more than 10 mol percent of the unsaturated organic carboxylic compound such as crotonic acid, its alkali metal salts are too sensitive to the high relative humidities used in weaving sized yarns, and do not have the proper hardness and body under such conditions to be useful as a sizing material. On the other hand, if the copolymer contains less" than 2 mol percent of the unsaturated organic carboxylic compound such as crotonic acid, its alkali metal salts are not soluble in aqueous solutions of caustic soda or sodium carbonate and it is not possible touse such salts for sizing textile warp yarns.

The copolymers of this invention may be prepared from vinyl acetate and a large variety of unsaturated organic carboxylic compounds containing from 3 to. 9 carbon atoms and having at leastone carboxyl group. As examples of such unsaturated organic carboxylic compounds may be mentioned the ethylenically unsaturatedaliphatic where n is a whole number from 3-to 6,-and which are polymerizable with vinyl acetate, -'are useful in preparing the copolymersof this invention. Of the above group of acids croton ic acid ispreferred because it is available commercially and copolymerizes withvinyl'acetate' to give superior copolymersfor use in sizing textile-warp yarns.

"further examples of unsaturated organic carb'oxylic ccmpounds'containing from? to 9 carbon atoms and having at leastone carboxyl-group may be mentioned the cthylenically unsaturated orga-ni c polybasic carboxylic acids whichare polyrncrizable with vinyl acetate-such as the relatively-water-insoluble ethylenically unsaturated aliphaticdicarboxylic acids of which -fumaric and itaconic acids are examples. Of these acids fumaric acid is preferred because it is available commercially. i

As further examples of unsaturated organic carboxylic compoundscontaining from 3-to 9 carbon atoms and having at least one carboxyl group may be mentioned the partial esters of ethylenically unsaturated aliphatic dicarboxylic acids polymerizable' with vinyl acetate, and preferably the alkyl half esters of such acids. As examples of such partial esters may be mentioned the alkyl half esters of maleic acid, in which the alkyl group contains from 1 to 4 carbonatoms, such as methyl, ethyl and propyl-acid maleate; the alkylhalf esters of fumaric acid, in which the alkyl group contains from 1 to 4 carbon atoms such as methyl acid fumarate and secondary butyl acid fumarate; the alkyl half esters of citraconic acid, in which the alkyl group contains from lto 4 carbon atoms, such as methyl and butyl acid citraconates; alkyl half esters-of chlorlmaleic acid, in which the alkyl group con tains from 1 to '4 carbon atoms, 'such as ethyland butyl acid chlormaleates; and alkylrhalf esters of itacqnic acid, inwhich thealkyl groupcontainsfrom l to 4 carbon atoms, such as nieth-yland butyl acid itaeonales, and the like. These esters with the exception Tofu-the allryl acid itaconates are represented generally by the str uctural formula:

Where X ishyd hs h halo e .tpte hr h ch or n or a al l pha' n at m stnumbe ,ofrmhhn atoms suchthat .the total number pf carbon 'atoms in the ester does not exceed- 9, and where vX1 is the same as, X or is p e a y y ro n wh n X is ot e than hy r and where R is an alkyl group haYingfrom l to 4 carbon 7 .With the processes of this invention. a

It is to he understood that. the'low molecular weight copolymers described herein may comprise vinyl acetate andmixtures of the unsaturated acids' and estershereinbefore described as, for example, low molecular weight copolymers of vinyl acetate, crotonic acid and alkyl half esters of maleic acid, in which the alkyl group contains from 1 to 4 carbon atoms, copolymers of vinyl acetate,

crotonic acid and acrylic acid and the like.

The preferred copolymers of this invention from the standpoint of proportions of ingredients are the low molecular weight copolymers of 95 to 97 mol percent of vinyl acetate and from 5 to 3 mol percent of the unsaturated organic carboxylic compounds hereinbefore described. The preferred copolymers of this invention from the standpoint of molecular weight are the copolyrners which have a molecular weight such that a molar solution of the copolymer in 99.5% by weight ethanol and 0.5% by weight of benzene have a viscositybetween about 7 and 12 centipoises at C. The preferred copolymers of this invention from the standpoint of ingredients employed are the copolymers of vinyl acetate and crotonic acid, the copolymers of vinyl acetate and alkyl half esters of maleic acid, in which the alkyl group contains from 1 to 4 carbon atoms, more preferably the methyl half ester, and the copolymers of vinyl acetate, crotonic acid and alkyl half esters of maleic acid, in which the alkyl group contains from 1 to 4 carbon atoms, more preferably the methyl half ester.

Thelow molecular weight copolymers of this invention are suitably prepared by adding vinyl acetate monomer and the unsaturated organic carboxylic compound in the proportions desired in the copolymer to an aqueous solu-' tion, preferably having a pH of 4 to 7, in the presence of at least 1% by weight, based on the Weight of the monomers, of a polymerization catalyst, preferably an oil soluble peroxide catalyst such as benzoyl peroxide and a protective colloidsuspending agent such as a watersoluble polyvinyl alcohol, the aqueous solution being at least at the reflux temperature at atmospheric pressure of the mixture obtained by the addition of the monomers t the aqueo utio a t erea te ,mh ht h hslhi mperatu of th mix re a ea t a t r flu e e ture ,of the mixture at atmospheric pressure until the reflu emp ure ise t a ha t Th hw SQ UI Qh is sti ed c ns a th hout e fhrhsqihg prh e ur The hl me zht hh mix ur i t ea cooled and the copolymer, which has been formed, is a a ed t ai th qheh Pha e by .d t ihn tr t on or he rifhgh qh P ef r bl b fi tr t dried.

1h Carrying ou the fore Pro ss i i desirable to add from about 1 to 11 parts by weight of the mono rners to from about 12 to 9 parts' by weight. of the aqueous Q m QB- .I ord t t h th m9$ h h hht h t ahd'h y ld o th 9PQ X ?I t is P ef e id a d from about 4 to 11 partsby weight of the monomersito from about ;1 2 to 9 parts by weight of the aqueous solution. Moreoyen'it is preferred to the vinyl acetate monome nd th hh athr hd q ahh h hhr' l com? pou and t a th r u tin ht th to t e h h h u i n- I s al des rabl t ad hermqhha hr t th aq eqh o ht hn t mo e .9: ha n t n We Pi ably at a substantially c c .u1stant rate. 'Iherateof addition of the monomers may be varied to some extent. I-Iow ar a if the ra eh add hh tth mo omer iS-thh i P th is a t e t P o e a .hh -hhfihhhihhdYh h wh chis on n rfl sh uhlh hh h oh 7 1 5051 9 hst soda at a pH between-about 7.5 and 9. If the rate of addition of the monomer is tqo slow the reaction time is unduly prolonged which leads to the formation of a partial m l h th 99P01Ym 1 t l 9 f :P an consequent difiiculty in separating the copolymer from the aqueous phase. Satisfactory results have been obtained by adding the monomers to the aqueous solution n the p enhe f the r t ht v hq lh d d agent .a t ete;hf-.ab ht: -0 t pelt b weight of h m nome P3111 1 h aw ;Q0-;.P t$;=hv yeight'bf h i qh 9 l i P- Bes :I l 1 ;5 have hhe hh a h y d n -th on mer atthh-r t fahh 1 0 :14 Parts hy'w i f th mo ome p r ho towe 00 Parts by weight of the aqueous solution. 7 7

The use of a polymerization catalyst is;,e sse ntial and p the minimum amount of catalyst used is critical if a low molecular weight copolymer and an eflicient reaction rate is to be obtained. It has presently been found necessary to use at least 1% by Weight of a polymerization catalyst based on the monomers, in the case of the oil soluble peroxide type catalysts such asbenzoyl peroxide, acetyl peroxide, tertiary-butyl hydroperoxide, cumene hydroperoxide, lauryl peroxide, methyl ethyl ketone peroxide and the like, and in the case of other oil soluble catalysts such as tertiary butyl perbenzoate, ditertiary-butyl perphthalate and the like. Even larger amounts of water-soluble polymerization catalysts such as hydrogen peroxide and the inorganic per catalysts such as potassium persulfate are required because such catalysts tend to decompose in the aqueous phase of the polymerization mixture. In general, satisfactory results are obtained with from about 1 to 5% by weight of the oil-soluble catalysts, based on the monomers. However, it is preferred to use from about 1.5 to 3.5% by weight of such catalysts based on the monomers. When using the oil soluble catalysts it is preferred to incorporate them in a mixture of vinyl acetate monomer and the unsaturated organic carboxylic compound. In the case of the water-soluble polymerization catalysts, it is usually desirable to use at least 3% by weight of such catalysts, based on the monomers, and generally up to by weight. Such catalysts are preferably added to the aqueous phase of the polymerization mixture.

The preferred catalysts are the oil-soluble peroxide type, and more preferably benzoyl peroxide.

An essential feature of the polymerization process of this invention is the use of a water-soluble protective colloid suspending agent such as polyvinyl alcohol in order to obtain the copolymer in bead form so that it is readily separated from the aqueous phase of the polymerization mixture. The amounts of such agent used are critical if coagulation of the copolymer or the formation of fine particles which are difficult to recover is to be avoided. The amount of suspending agent will vary to some extent depending on the particular agent used, the rate of stirring of the polymerization mixture and the polymer to water ratio in the polymerization mixture. If the amount of suspending agent used initially is too small coagulation or coalescence of the copolymer beads occurs. This in itself is not objectionable since it has presently been found that the copolymer beads are dispersed if more suspending agent is added. The important factor is that the total amount of suspending agent used should be sufiicient to obtain the copolymer in bead form. If the amount of suspending agent employed is too high the copolymer forms as fine particles which are quite diflicult to separate from the aqueous phase. In general, it has presently been found necessary to use at least 0.11% by weight of the suspending agent, based on the copolymer, at the lower weight ratios of monomer to aqueous solution, and at least 0.125% by weight of the suspending agent, based on monomers, in the preferred range of about 4 to 11 parts by weight of the monomers to about 12 to 9 parts by weight of the aqueous solution. The maximum amount of suspending agent used should not exceed about 1.0% by weight of the monomers, and preferably'should not exceed about 0.5% by weight of the monomers at any monomer to aqueous solution weight ratio, otherwise the copolymer particles are too fine for efficient recovery. As examples of water-soluble protective colloid suspending agents which may be used in the process of preparing the copolymer may be mentioned water-soluble polyvinyl alcohol, water-soluble copolymers of vinyl acetate and maleic anhydride, gelatin, water-soluble natural gums, gum tragacanth, water-soluble starch, polyacrylic acid, polymethacrylic acid and the like.

Various additives may be used in addition to the catalyst and suspending agent. For example, it is possible to use small amounts of surface active agents, preferably anionic surface active agents such as alkali metal salts of alkyl benzene sulfonic acids, in which the alkyl chain contains at least 10 carbon atoms, alkali metal salts of sulfonated or sulfated fatty alcohols or fatty acids containing at least 10 carbon atoms, alkali metal salts of dialkyl esters of sul-fosuccinic acid, in which the alkyl groups contain at least 4 carbon atoms, and the like. Such agents aid in preventing the accumulation of copolymer beads on the walls of the reaction vessel. However, if too much surface active agent is used the copolymer forms as small particles which are difficult to separate from the aqueous phase. Accordingly, it is preferred to use very small amounts of such agents, that is, less than 0.2% by weight, based on the monomers, and more preferably between about 0.001% and 0.1% by weight. It is also possible to use small amounts of modifying agents to control the length of the copolymer chains, for example, agents such as alkyl mercaptans, especially dodecyl mercaptan, carbon tetrachloride and the like.

The temperature used during the polymerization reaction is important, and the polymerization should be carried out at least at the reflux temperature of the mixture at atmospheric pressure. Higher temperatures may be used by carrying out the polymerization at super-atmospheric pressures; For example temperatures up to 130 C. may be used. When the polymerization is carried out at atmospheric pressure, that is, at an absolute pressure of about 760 millimeters of mercury, under a reflux condenser, the reflux temperature is initially between about 65 and 70 C. As the polymerization proceeds and substantially all of the vinyl acetate is copolymerized with the unsaturated organic carboxylic compound the refiux temperature increases and the temperature of the polymerization mixture is raised accordingly. in general, when the reflux temperature at atmospheric pressure increases to at least 75 C., the polymerization is substantially complete, although it is preferred to continue the reaction until the reflux temperature at atmospheric pressure is at least C. in order to obtain the optimum yields. The copolymer beads may be separated at this point, after the polymerization mixture is cooled, but it is preferred to pass a current of air over the surface of the polymerization mixture while maintaining the temperature of the mixture until a major portion of the unreacted vinyl acetate monomer has been removed.

After the polymerization mixture is cooled to a suitable temperature, for example, a temperature of about 20 to 50 C., it is preferred to pour the mixture into cold water at a temperature of 30 C. or lower to precipitate the copolymer beads from the mixture. After the copolymer beads have been separated from the mixture, it is preferred to wash the beads with cold water at a temperature below 30 C. to remove impurities. The wet beads may be dried at any temperature, but higher temperatures cause the beads to coalesce and to form a large mass which is difficult to dissolve in aqueous alkali unless the mass is comminuted. It is accordingly preferred to dry the beads at temperatures below 35 C. while stirring the beads, more preferably under a vacuum.

The foregoing process produces beads of the copolymers, which beads are between about 0.15 and 1 millimeter in diameter. Moreover, the process is capable of preparing copolymers having a molecular weight such that a molar solution of the copolymer in 99.5% ethanol and 0.5% benzene has a viscosity below about 18 centipoises but not below 7 centipoises at 20 C.

The present invention is also directed to alkali metal salts of the low molecular weight copolymers hereinbefore described. It has presently been found that the alkali metal salts of the copolymers of this invention are especially suitable for sizing textile warp yarns. Thus, they not only have good adhesion to most textile warp yarns such as cotton, regenerated cellulose and cellulose acetate warp yarns, but they give excellent protection to the warp yarns during weaving and are readily removed from the fabric after weaving by scouring the fabric in and sized yarns of this invention will be obtained from the following specific examples which are intended to illustrate this invention, but not to limit the scope thereof, parts and percentages being by weight. The first two examples illustrate the copolymers of this invention and the process of preparing such copolymers. The remaining examples illustrate the sizing processes and sized yarns of this invention.

Example I Six hundred cubic centimeters of water, 0.25 gram of medium viscosity polyvinyl alcohol and 0.5 milliliter of a aqueous solution of the sodium salt of the dioctyl ester of sulfo succinic acid were charged to a glass reaction vessel equipped with a stirrer, a reflux condenser and a dropping funnel. This solution was first heated to 65 C. with vigorous stirring and a monomer mixture consisting of about 194 grams of monomeric vinyl acetate, 6 grams of monomeric crotonic acid and 4 grams of benzoyl peroxide was then added at a substantially constant rate, the rate being adjusted so that substantially all of the monomer mixture was added over a period of 3 hours. During the monomer addition the temperature of the resulting mixture was maintained at the reflux temperature which was about 65 C. and the mixture was continuously stirred. After all of the monomer mixture had been added the temperature of the mixture was maintained at the reflux temperature of the mixture until the reflux temperature rose to 80 C. Air was then sucked over the polymerization mixture to remove unreacted vinyl acetate. The polymerization mixture, which contained beads of a copolymer of vinyl acetate and crotonic acid, was then cooled to 40 C. with stirring and poured into an equal volume of cold water at a temperature of about 20 C. to precipitate the copolymer beads. The polymerization mixture was then filtered through cotton sheeting and the copolymer beads were washed thoroughly with cold water. The wet beads thus obtained were then dried, while stirring the beads, under a vacuum at a temperature of 30 C.

The copolymer obtained according to the foregoing procedure was soluble in an aqueous solution of caustic soda at a pH of about 7.8, and contained about 97 mol percent of combined vinyl acetate and 3 mol percent of combined crotonic acid. This copolymer lrad a molecular weight such that a molar solution of the copolymer in 99.5% ethanol and 0.5% benzene had a viscosity of about 9.7 centipoises at 20 C. Solutions of alkali metal salts of the copolymer were readily prepared by dissolving 5 parts of the copolymer in 100 parts of water containing sufiioient alkali metal hydroxide to provide a solution having a pH of 8.0. Films prepared from such solutions to which had been added a water-soluble blue dye, and dried and then baked for 30 minutes for 250 F. dissolved within aperiod of about 30 seconds in an excess of water at 40 C.

Films of alkali metal salts of high molecular weight copolymers of vinyl acetate and crotonic acid having'a molecular weight such that a molar solution of the copolymer in a solution of 99.5% ethanol and 0.5% benzene had a viscosity of 28 centipoises at 20 C. were prepared in the same manner. Such films did not dissolve in an excess of water at 40 C. within a practical period of time.

Example II Six hundred cubic centimeters of water, 0.25 gram medium viscosity polyvinyl alcohol and 0.5 milliliter of a 5% aqueous solution of the sodium salt of the dioctyl ester of sult'o succinic acid were charged to a glass reaction vessel equipped with a stirrer, a reflux condenser and a dropping funnel. This solution was first heated to a temperature of 65 C. with vigorous stirring and a monomer mixture of 181 grams of vinyl acetate, 14.5 grams of methyl half ester of maleic acid and 4 grams of benzoyl peroxide was then added at a substantially constant rate of about 1.1 gram per minute, which monomer addition required about 3 hours. During the monomer addition to the temperature of the water-monomer mixture was maintained at the reflux temperature which was about 67 C. at atmospheric pressure, and the mixture was stirred continuously. After all of the monomer mixture had been added the temperature of the polymerization mixture was maintained at the reflux temperature of the mixture until the reflux temperature rose to C. Thereafter air was sucked over the polymerization mixture to remove unreacted vinyl acetate monomer. The polymerization mixture thus obtained contained beads of a copolymer of vinyl acetate and methyl half ester of maleic acid, and this mixture was then cooled to a temperature of 40 C. with stirring and poured into an equal volume of cold water at a temperature of about 20 C. to precipitate the copolymer beads. The resulting mixture was filtered through cotton sheeting and the beads of the copolymer were then washed thoroughly with cold water and finally :air dried while stirring the beads.

The copolymer obtained according to the procedure described immediately above was soluble in an aqueous solution of caustic soda at a pH of about 7.5, and contained (about mol percent of combined vinyl acetate and about 5 mol percent of combined methyl acid maleate. This copolymer had a molecular weight such that a molar solution of the copolymer in 99.5% ethanol and 0.5% benzene had a viscosity of about 10.1 centipoises at 20 C. Films prepared from equeous solutions of a wlater-soluble blue dye and alkali metal salts of such copolymer and then dried and finally baked for 30 minutes at 250 F. dissolved within a period of about 45 seconds in an excess of water at 40 C.

Example 111 A solution of the sodium salt of the copolymer of Example II was prepared by adding 8 parts of dry beads of the copolymer to 92 parts of water with stirring and the slow addition of 0.65 part of sodium hydroxide, while maintaining the temperature of the water at 180 F. The solution thus obtained had a pH of 7.8 (glass electrode). This solution was charged to the size box of a slasher and maintained at a temperature of F.

Seventy five filament, twenty four denier cellulose acetate yarns having a twist of 28 turns per inch were drawn through the size solution, as prepared above, at the rate of 10 yards per minute and then passed between squeeze rolls adjusted to give a solution pick-up of 25% based on the dry yarn weight so as to deposit about 2% of copolymer salt based on the dry yarn. The wet yarns were then passed over 5 rotating drying cans arranged in tandem, which cans were maintained at temperatures of 180 F., 200 F., 200 F., 200 F., and F., respectively, to dry the yarns, after which the yarns were taken up on a beam. No foaming of the solution or size accumulation on the drying cans was noted during the sizing procedure.

The weaving efiiciency of the sized yarns at a relative humidity of about 60% was excellent. The size was substantially completely removed from the woven fabric by scouring the fabric in warm water.

Example IV Forty filament, one hundred and fifty denier cellulose acetate yarns having a twist of 2.5-8 turns per inch were sized using the same solution and procedure described in Example Ill. The weaving efficiency of the sized yarns was excellent, and the size was substantially completely removed from the yarns by scouring in warm water.

Example V Twenty two and two-tenths pounds of dry beads of the copolymer prepared according to Example I and three and eight-tenths pounds of sodium bicarbonate were added 75 to 75 gallons of water with vigorous agitation, the water r I 1 temp ratu e i it all beihg 1 he mix ure a atedte 130;F- su s nt a ly eemp ete o ion o theeei hmsah of th eep yhierv s thus obtained in about 70 minutes. The resulting mixture was then diluted with 100 gallons of cold water, with stirring, and a portion of the diluted solution was charged to the size box 9i h s ashe a main ned a 35- Thirty seven hundred and thirty-five ends of 150 filament. 40 den e is es rayon a n a n 'a t st of two turns per inch were drawn through the size solution at the rate of 575 yards per minute and then padded betw en ue z rolls a ju d at a pres e o p n Pe l hea t h a o' ep i bou 6% of t er l ms sa t bas en he ht f h y y s, Th wet yarns were then dried by passing them at a rate of 55 a d Pe m nu v 7 r t t n ry n ne which e ear a sed i n'es. th ry a be maintained at temperatures of 1 5., 190 F., 215 3, 220 F., 205 F., 190 1 and 180 R, respectively, after which hey were ee lee e n a eam N0 foam n 0f t Si o ahead 10 a cumul ion o in m e ia o the 6ry ee s e e n fie du h z n o e Thesized warp yarns were woven into a fabric at a relative humidity of 75%. The weaving efficiency was excellent and no accumulation of size was noted on the moving parts of the loom during the weaving operation. The size was readily removed from the warp yarns of the f arbic by securing the fabric in warm water.

Example VI One hundred parts of the copolymer of Example I and twelve parts of sodium bicarbonate were stirred into 2128 parts of hot water until the copolymer dissolved to form a solution of the sodium salt of the copolymer. This solution, which had a pH of about 8.2, was charged to the size box of a slasher and maintained at a tem perature of 140 F.

Iwenty four filament, seventy five denier cellulose acetate yarns having a twist of 2-8 turns per inch were drawn through the above solution at a rate of 10 yards per minute and then passed between squeeze rolls which were adjusted to pick up about of the solution, based on the dry yarns, so as to deposit about 2% copolymer salt based on the dry yarns. The yarns were then dried bypassing them over 5 rotating dry canswhich were maintained at temperatures of 180 F., 200 F., 200 F., 200- F., and 160 F., respectively. No foam ing of the size solution and no size accumulation on the dry cans was noted.

The filaments of the sized yarns were well closed and the sized yarn were supple and yet appreciably stilfened. Thesize coating on the yarns had excellent adhesion and did not crack or dust off on flexing the. yarns. The size coating was easily removed from the yarns by simple scouring in warm water.

Examples III through VI illustrate the sizing of regenerated cellulose and cellulose acetate filament yarns, but it is to be understood that the sizing processes of this invention may also be used to size spun yarns, that is, yarns prepared from natural fibers or synthetic staple fibers or mixtures thereof, or from other types of textile yarns. As examples of textile yarns which may be sized by the processes of this invention may be mentioned natural cellulose yarns such as cotton yarns, linen yarns, rarnie yarns and the like; natural keratinous yarns such as. wool yarns, yarns prepared from mixtures of wool with other animal fibers such as mohair fibers, camel hair and the like; regenerated cellulose yarns prepared from cuprammonium and viscose spinning solutions; yarns prepared from organic derivatives of cellulose such as cellulose acetate, ce lulose propionate and the like; yarns Pr pa e mfi forming synthe po ymer ueh as l qli qqrylonitrile and its copolymers, copolymers of yinyl' acetate and vinyl chloride, condensation products of ethylene glycol and terephthalic acid and the like; and

. 12 ya n prepa d t am pl dt xt l yarns o xt es of the e esdin na ura fib r nd synt ti s p fi e he si in Pr e s of th n n i n re n t int n d o includ the siz of ya n p p solely m ne synthetic polyaljnidfi of aliphatic dibasic carboxylic acids nd al ph t c iamin a f amp po y mid s of adipic acid and hexamethylene diamine. The sizing processes of this invention haveheen found to be especial ly suitable for the sizing of regenerated cellulose and 9 9 4% ethanol and /g% ture at least at the reflux boxylic compound is cellulose acetate yarns, and the sizing of such yarns is preferred because of the excellent results obtained.

.Various modifications may be made in the copolymers, processes and sized yarns described herein as will be apparent to those skilled in the art to which this invention appertains without departing from the spirit and. intent of this invention. Accordingly, it is to be understood that it is not intended to limit this invention except by the scope of .theappended claims.

What is claimed is:

1. A process of producing copolymers of 90 to 98 mol percent of vinyl acetate and 10 to 2 molpercent of an ethylenically unsaturated organic carboxylic compound, which copolymer is in the form of beads and has a molecular weight such that a molar solution of the copolymer in 99 /z% ethanol and /z% benzene has a viscosity below 18 centipoises but not below 7 centipoises at 20 C., which comprises adding with stirring in the stated proportions vinyl acetate monomer and an ethylenically unsaturated organic carboxylic compound copolymerizable with vinyl acetate containing from 3 m9 carbonatoms and having l to 2 carboxyl groups, to an aqueous solution which is at least at the reflux temperature at atmospheric pressure of themixture thus obtained, in the presence insaid aqueou solution of a protective colloid suspending agent selected from the group consisting of watersoluble polyvinyl alcohol, water-soluble copolymers' of vinyl acetate and maleic anhydride, gelatin, water-soluble natural gurus, gum tragacanth, water-soluble starch, polyacrylic acid and polymethacrylic acid and 1 to 10% by weight, based on the monomers, of a peroxygen polymerization catalyst, the weight ratio of total monomers to aqueous solution being from about 1 to 11 parts by weight of monomer to from about 12 to 9 parts by weight of said solution, said monomers being added to said aqueous solution at the rate of about 10 to 17 parts by weight-of the monomers per hour for every 100 parts by weight of said solution, maintaining the temperature of the resulting mixture at least at the reflux temperature of the mixture at atmospheric pressure during the addition of the monomers, the total amount of said suspending agent employed in said aqueous solution during the addition of the monomers being at least 0.11% by weight but not in excess of 1% by weight, based on the monomers, thereafter maintaining the temperature of the mixtemperature at atmospheric pressure until the reflux temperature rises to at least C., whereby by carrying out the aforedescribed steps the co-. polymer is produced in the form of beads, cooling the mixture, separating the copolymer beads formed during the reaction from the mixture and drying the copolymer heads.

2. A process according to claim 1, but further characterized in that the ethylenically unsaturated organic carcrotonic acid. V

3. A process according to claim 1, but further characterized in that the ethylenically unsaturated organic carboxylic compound is an alkyl half ester of maleic acid, in which the alkyl group contains from 1 to 4 carbon atoms.

4. A process of producing copolymers of to 98 mol percent of .vinyl acetate and 10 to 2 mol percent of an ethylenically. unsaturated organic carboxylic compound, which copolymer is in head form and weight suchthat .a molar solution of the copolymer in benzene has a viscosity below 18 centipoises but not below 7 centipoises at 20 C., which has a molecular comprises adding with stirring in the stated proportions a mixture of vinyl acetate monomer and an ethylenically unsaturated organic carboxylic compound copolymerizable with vinyl acetate containing from 3 to 9 carbon atoms and having 1 to 2 carboxyl groups, to an aqueous solution in the presence of about 1.5 to 3.5% by weight of an oil-soluble peroxide polymerization catalyst, based on the monomers, and a protective colloid suspending agent selected from the group consisting of water-soluble polyvinyl alcohol, water-soluble copolymers of vinyl acetate and maleic anhydride, gelatin, water-soluble natural gums, gum tragacanth, water-soluble starch, polyacrylic acid and polymethacrylic acid, said aqueous solution being at the reflux temperature at atmospheric pressure of the mixture obtained by adding the monomers to said solution, said monomers being added at a substantially constant rate such that about 10 to 17 parts by weight of the monomers are added per hour for each 100 parts by weight of said aqueous solution, the weight ratio of total monomers to aqueous solution being from about 4 to 11 parts by weight of the monomers to 12 to 9 parts by weight of said aqueous solution; maintaining the resulting mixture at the reflux temperature of the mixture at atmospheric pressure during the addition of said monomer, the total amount of said suspending agent employed in said aqueous solution during the addition of monomers being between about 0.125 and 0.5% by weight, based on the monomers; thereafter maintaining the temperature of the mixture at the reflux temperature of the mixture at atmospheric pressure until the temperature rises to at least 80 C., whereby by carrying out the aforedescribed steps the copolymer is produced in the form of beads; passing a current of air over the surface of the mixture while maintaining the temperature of the mixture until a major portion of unreacted vinyl acetate is removed; cooling the mixture; adding the mixture to cold water to precipitate the copolymer beads; separating the precipitated copolymer beads from the liquid phase of the mixture; and then drying the copolymer beads.

5. A process according to claim 4, but further characterized in that the protective colloid suspending agent employed is water-soluble polyvinyl alcohol.

6. A process according to claim 5, but further characterized in that the ethylenically unsaturated organic carboxylic compound employed is crotonic acid.

7. A process according to claim 5, but further characterized in that the ethylenically unsaturated organic carboxylic compound employed is an alkyl half ester of maleic acid, in which the alkyl group contains from 1 to 4 carbon atoms.

8. A process according to claim 4, but further characterized in that the ethylenically unsaturated organic carboxylic compound employed is the methyl halt ester of maleic acid.

9. A process according to claim 4, but further characterized in that the polymerization reaction is carried out in the presence of about 0.001 to 0.1% by weight of an anionic surface active agent selected from the group consisting of alkali metal salts of alkyl benzene sulfonic acids, in which the alkyl chain contains at least 10 carbon atoms, alkali metal salts of sulfonated alcohols and sulfonated fatty acids containing at least 10 carbon atoms, alkali metal salts of sulfated fatty alcohols and fatty acids containing at least 10 carbon atoms and alkali metal salts of dialkyl esters of sulfosuccinic acid, in which the alkyl groups contain at least 4 carbon atoms.

10. A process of producing copolymers of to 97 mol percent of vinyl acetate and 5 to 3 mol percent of crotonic acid, which copolymer is in the form of beads and has -a molecular weight such that a molar solution of the copolymer is 99 /2% ethanol and 16% benzene has a viscosity below 18 centipoises but not below 7 centipoises at 20 C., which comprises adding with stirring in the stated proportions vinyl acetate monomer and crotonic acid monomer to an aqueous solution of at least 0.11% by weight but not in excess of 1% by weight, based on the total monomers added, of water-soluble polyvinyl alcohol and from 1 to 10% by weight, based on the total monomers added, of a peroxygen polymerization catalyst, said aqueous solution being maintained at least at the reflux temperature at atmospheric pressure of the mixture thus obtained prior to and during the addition of said monomers, the weight ratio of total monomers to aqueous solution being from about 1 to 11 parts by weight of the monomers to from about 12 to 9 parts by weight of said solution, said monomers being added to the aqueous solution at the rate of about 10 to 17 parts by weight of the monomers per hour for every 100 parts by weight of said solution, maintaining the temperature of the mixture obtained after the addition of the monomers at the reflux temperature at atmospheric pressure until the reflux temperature rises to at least 75 C., whereby by carrying out the afore-described steps th copolymer is produced in the form of beads, cooling the mixture, separating the copolymer beads from the mixture and drying the copolymer beads.

References Cited in the file of this patent UNITED STATES PATENTS 1,976,679 Fikentscher et al Oct. 9, 1934 2,196,752 Dickey Apr. 9, 1940 2,234,722 Dickey et a1 Mar. 11, 1941 2,263,598 Starck et a1. Nov. 25, 1941 2,300,566 Hahn et a1. Nov. 3, 1942 2,356,879 Pense et a1. Aug. 29, 1944 2,637,712 Upton May 5, 1953 2,643,245 Wilson June 23, 1953 2,643,246 Wilson June 23, 1953 FOREIGN PATENTS 59,092 Denmark Oct. 6, 1941 499,917 Belgium Dec. 30, 1950 803,956 Germany Apr. 12, 1951 

1. A PRECESS OF PRODUCING COPOLYMERS OF 90 TO 98 MOL PERCENT OF VINYL ACETATE AND 10 TO 2 MOL PERCENT OF AN ETHYLENICALLY UNSATURATED ORGANIC CARBOXYLIC COMPOUND WHICH COPOLYMER IS IN THE FORM OF BEADS AND HAS A MOLECULAR WEIGHT SUCH THAT A MOLAR SOLUTION OF THE COPOLYMER IN 991/2% ETHANOL AND 1/2% BENZENE HAS A VISCOSITY BELOW 18 CENTIPOISES BUT NOT BELOW 7 CENTIPOISES AT 20%C., WHICH COMPRISES ADDING WITH STIRRING IN THE STATED PROPORTIONS VINYL ACETATE MONOMER AND AN ETHYLENICALLY UNSATURATED ORGANIC CARBOXYLIC COMPOUND COPOLYMERIZABLE WITH VINYL ACETATE CONTAINING FROM 3 TO 9 CARBON ATOMS AND HAVING 1 TO 2 CARBOXYL GROUPS, TO AN AQUEOUS SOLUTION WHICH AT LEAST AT THE REFLUX TEMPERATURE AT ATMOSPHERIC PRESSURE OF THE MIXTURE THUS OBTAINED, IN THE PORESENCE IN SAID AQUEOUS SOLUTION OF A PROTECTIVE COLLOID SUSPENDING AGENT SELECTED FROM THE GROUP CONSISTING OF WATERSOLUBLE POLYVINYL ALCOHOL, WATER-SOLUBLE COPOLYMERS OF VINYL ACETATE AND MALEIC ANHYDRIDE, GELATIN, WATER-SOLBLE NATURAL GUMS, GUM TRAGACANTH, WATER-SOLUBLE STARCH, POLYACRYLIC ACID AND POLYMETHACRYLIC ACID AND 1 TO 10% BY WEIGHT, BASED ON THE MONOMERS, OF A PEROXYGEN POLYMERIZATION CATALYST, THE WEIGHT RATIO OT TOTAL MONOMERS TO AQUEOUS SOLUTION BEING FROM ABOUT 1 TO 11 PARTS BY WEIGHT OF MONOMERS TO FROM ABOUT 12 TO 9 PARTS BY WEIGHT OF SAID SOLUTION, SAID MONOMERS BEING ADDED TO SAID AQUEOUS SOLUTION AT THE RATE OF ABOUT 10 TO 17 PARTS BY WEIGHT OF THE MONOMERS PER HOUR FOR EVERY 100 PARTS BY WEIGHT OF SAID SOLUTION, MAINTAINING THE TEMPERATURE OF THE RESULTING MIXTURE AT LEAST AT THE REFLUX TEMPERATURE OF THE MIXTURE AT ATMOSPHERIC PRESSURE DURING THE ADDITION OF THE MONOMERS, THE TOTAL AMOUNT OF SAID SUSPENDING AGENT EMPLOYED IN SAID AQUEOUS SOLUTION DURING THE ADDITION OF THE MONOMER BEING AT LEAST 0.11% BY WEIGHT BUT NOT IN EXCESS OF 1% BY WEIGHT, BASED ON THE MONOMERS, THEREAFTER MAINTAINING THE TEMPERATURE OF THE MIXTURE AT LEAST THE REFLUX TEMPERATURE AT ATMOSPHERIC PRESSURE UNTIL THE REFLUX TEMPERATURE RISES TO AT LEAST 75*C., WHEREBY BY CARRYING OUT THE AFOREDESCRIBED STEPS THE COPOLYMER IS PRODUCED IN THE FORM OF BEADS, COOLING THE MIXTURE, SEPARATING THE COPOLYMER BEADS FORMED DURING THE REACTION FROM THE MIXTURE AND DRYING THE COPOLYMER BEADS. 